One basic component of a semiconductor device is a transistor, commonly referred to as a FET. Various types of FET devices exist, and the function, composition, and use of FET devices varies. One type of FET device commonly used in semiconductor devices is a metal-oxide-semiconductor field effect transistor (MOSFET). MOSFET devices generally come in two distinct types, p-channel MOSFET (pMOS) devices, and n-channel MOSFET (nMOS) devices. Digital-data processing devices may include a combination of pMOS and nMOS devices, which are arranged in a complimentary metal-oxide-semiconductor (CMOS) arrangement. Transistor size constraints in advanced semiconductor devices have required more compact transistor designs and topologies. One such design includes a transistor device that has multi-gate structures that are combined to provide scalable CMOS circuits for digital applications.
Some semiconductor devices use horizontal nanosheets (hNS) or horizontal nanowires (hNW) shaped channels for the transistor devices, which will be respectively referred to herein as hNS devices or hNW devices. In hNS devices, at least some of the channels of the device are shaped as nanosheets that are surrounded by gate-all around structures. Nanosheets are structures having one scaled dimension that is typically in the range of about 2 nm to about 10 nm, while the other dimensions may be larger (e.g., in a range of about 10 nm to about 100 nm). When used in channels of MOS devices surrounded by gate-all around structures, the hNS may have a cross-section (normal to the direction of current flow in the channel) that typically has a smaller dimension (e.g., of about 2 nm to about 10 nm) and a larger dimension (e.g., of about 10 nm to about 100 nm). When the two dimensions of the cross-section of the hNS are similar (e.g., both in a range of about 2 nm to about 10 nm), it is referred to as NW. Although the present embodiments are primarily described in relation to hNS devices, it should be understood that the embodiments disclosed herein may be equally applied to hNW devices. During processes of fabricating hNS or hNW structures, strain may be introduced in the channel or channels of the devices. The strain may be a physical or mechanical result of the materials and process sequences used in fabricating the structure. Also, varying strain may be caused by variations in physical dimensions of the hNS or hNW structures. Variations in strain parameters may affect performance of a device. The effects may be adverse, or may enhance the performance of the device, depending upon the device configuration and the value of the strain parameter.